All items in category Magazine Articles
R&D Stories: TPCD Technology in Headphones - Engineering to Control Diaphragm Resonances
by Martin Turesson

R&D Stories: TPCD Technology in Headphones - Engineering to Control Diaphragm Resonances

This article details how thin-ply carbon diaphragm (TPCD) technology can also be applied to headphones, allowing precise control of diaphragm resonances rather than trying to reduce its negative effects, as the speaker industry already recognizes. As the pioneer of TPCD technology, Composite Sound is now entering the over-ear headphone market with its Metamodal TPCD engineering approach, enabling headphones with better sound quality, improved bass performance, and higher sensitivity.
Read more...
New Ways to Measure Noise Cancelling, Transparency, and Other Modes in Headphones and Earphones
by Brent Butterworth

New Ways to Measure Noise Cancelling, Transparency, and Other Modes in Headphones and Earphones

Now that headphones and earphones are adding situational awareness, hearing protection and hearing enhancement features, HEAD acoustics created new test methods to evaluate these functions, faithfully simulating environments that a consumer might typically encounter when using products with these features. As an experienced reviewer in this category, Brent Butterworth was invited to visit HEAD acoustics' US headquarters in Brighton, MI, to learn about all the solutions the company has developed for this purpose, based on measurement techniques outlined in ETSI standards.
Read more...
Fresh From the Bench: Improving GaN with Digital Control
by Stuart Yaniger

Fresh From the Bench: Improving GaN with Digital Control

The AX5689 is an eight-channel audio amplifier controller IC with digital inputs and CMOS level PWM outputs, enabling high-order digital control loops with post-filter feedback. This article, originally published in audioXpress, December 2023, reviews the Axign and GaN Systems Class-D audio amplifier reference design board, intended to demonstrate the benefits of Axign's digital controllers and its unique approach.
Read more...
Patent Review: Air Motion Transformer Passive Radiator for Loudspeaker
by James Croft

Patent Review: Air Motion Transformer Passive Radiator for Loudspeaker

In the August 2018 issue of Voice Coil, James Croft combined the review of two important independent patents, having in common the fact that they try to address the shortcomings of the work of Dr. Oskar Heil with his Air Motion Transformer (AMT) woofer system. Following a review of a Tymphany patent, Croft reviewed a related patent for an Air Motion Transformer Passive Radiator, invented by and awarded to Eugene Julius Christensen (Aspen, CO).
Read more...
Development & Design: The Impact of Microphone Specifications on Active Noise Cancellation Performance
by Nikolay Skovorodnikov

Development & Design: The Impact of Microphone Specifications on Active Noise Cancellation Performance

Active noise cancellation (ANC) is a popular feature for consumer electronics headsets, headphones, and earbuds. Designing effective ANC imposes particular specification requirements on audio chain components, including microphones. This article explains how to achieve better true wireless stereo ANC designs, offering valuable insights for this trending application.
Read more...
Patent Review: Acoustic Transducer Comprising a Plurality of Coaxially Arranged Diaphragms
by James Croft

Patent Review: Acoustic Transducer Comprising a Plurality of Coaxially Arranged Diaphragms

This is a review of a design patent, submitted on behalf of Tymphany, trying to address the shortcomings of the work of Dr. Oskar Heil with his Air Motion Transformer (AMT) woofer system. The patent describes an acoustic transducer comprising one or more electromagnetic motors that drive one or more sets of multiple diaphragms to provide acoustically efficient loudspeaker systems in compact dimensions.
Read more...
R&D Stories: How Optical Technology Enables a Generational Shift in MEMS Microphone Performance
by Jakob Vennerød and Kieran Harney

R&D Stories: How Optical Technology Enables a Generational Shift in MEMS Microphone Performance

The article summarizes the evolution of MEMS microphone technology and describes the benefits of optical microphones over conventional solutions. This is a crucial reading to understand how the first generation of optical MEMS microphones have smashed the limits of SNR and dynamic range of miniature microphones, with 80dBA SNR (14dBA noise floor), 132dB dynamic range, 24-bit digital output and all with ultra-low power consumption.
Read more...
R&D Stories: Motion Feedback for Active Desktop Subwoofers
by Zami Schwartzman

R&D Stories: Motion Feedback for Active Desktop Subwoofers

Zami Schwartzman, the founder of Servobass, shares his journey into the application of Motion Feedback (MFB) methods for active subwoofers. He explores passive and active bass enhancement methods and how Servobass arrived at an optimized design using MFB techniques to achieve highly performing active subwoofers in desktop and compact sizes. A solution that is now available to be licensed by the industry. This article was originally published in audioXpress, November 2023.
Read more...
Getting to Know Dutch & Dutch
by Jan Didden

Getting to Know Dutch & Dutch

With a visit to Dutch & Dutch, Jan Didden unveils the journey of this innovative speaker manufacturer from The Netherlands. This company, founded in 2014, has so far achieved remarkable success with a single product designed to break the vicious cycle of speakers and room acoustics. The Dutch & Dutch 8c is a no-compromise active speaker designed to work together with the acoustics of the listening room.
Read more...
No Zipper, No Pop! How ADC Hybrid Gain Control Can Enable Smooth, Pop-Free Microphone Preamp Gain Changes
by Michael Chandler-Page

No Zipper, No Pop! How ADC Hybrid Gain Control Can Enable Smooth, Pop-Free Microphone Preamp Gain Changes

This article explains the new hybrid gain control (HGC) feature of Cirrus Logic’s latest CS530xP family of Pro Audio ADCs and how these can eliminate noise problems when changing gain on digitally controlled mic preamps. This solution enables fine-resolution mic preamp gain control, with the feel of a traditional potentiometer but without audible pops or zipper noise by integrating control into the ADC, together with zero-cross detection and precisely synchronized digital gain control.
Read more...